Cummings recalls the case in detail and explains how Roger Payne, an acquaintance of the victim, was finally nailed. Forensic scientists were able to identify fibres from Claire Joseph’s distinctive mohair dress on his coat, hat and suit, and fibres from him were found on Claire’s clothing and even under one of her nails.

Scores of fibres were eventually identified, illustrating the basic law of forensic science, that every contact leaves its trace. Roger Payne was found guilty of murder and sentenced to life.

The ‘Blue Serge Suit’

The second case in this episode shows how one single fibre can provide damning evidence in a case of murder. Known as the case of the ‘Blue Serge Suit’ it concerns the murder of young woman named Ruby Keen, at Leighton Buzzard.

There was alarm amongst Scotland Yard detectives when Ruby’s body was found in lovers’ lane as police questioning elicited descriptions of a young man, dressed in what looked like a policeman’s uniform, kanoodling with Ruby on the night of her death. 

Ruby’s fiancé was a policeman, and she had previously courted another member of the police force. But when another suspect, Leslie Stone, was questioned he too admitted owning a blue serge suit, quite similar to a police uniform. 

When this suit was examined it was found that though brand new, the knees had been brushed so hard that the nap had almost worn away, and embedded in the lining was found a single inch long silky strand which matched those from the undergarment that Ruby had been wearing at the time of her murder. 

At first Stone denied the murder, but in the witness box changed his story, saying that an argument had got out of hand, but that he’d had no idea that Ruby had died. This didn’t wash with the jury however, and he was found guilty of her murder and hanged.

• Read about the Murders in the Factory